Process for manufacturing timepiece dials



April 1952 c. STERN 2,594,820

PROCESS FOR MANUFACTURING TIMEPIECE nms Filed March 51, 1948 FIGS FIGS 1 E Patented Apr. 29, 1952 PROCESS FOR MANUFACTURING TIMEPIECE DIALS Charles Stern, Geneva, Switzerland Application March 31, 1948, Serial No. 18,249 In Switzerland April 10, 1947 3 Claims. 1

This invention relates to time-piece dials and has particular reference to a process of manufacturing time-piece dials having indicia members stamped in relief therefrom.

It is an object of the invention to provide time-piece dials of base metals or alloys having indicia members stamped in relief therefrom and electro-plated so as to appear in a colour and brightness different from that of the dialplate itself.

According to a chief feature of the invention, indicia members are stamped in relief from a plate of light metal or alloy such as, for instance, aluminium or magnesium or their alloys and the whole plate is subjected to an oxidizing treatment, preferably to anodic oxidation, the prominent indicia members are then polished to remove the oxide coating from their upper surface and make it electro-conductive and then electroplated whereas the remainder of the dial plate is insulated by the oxide coating.

The accompanying drawing illustrates the various steps of the invention.

Fig. l is a plan view of a watch dial embodying the invention.

The Figures 2, 3, 4 and 5 are enlarged sectional views taken on line A--A of Fig. 1 showing a portion of the dial after various steps of the manufacturing process.

In carrying out the process, I stamp indicia members in relief, for instance hour characters as 2 from a plate i made of light metal or alloy such as aluminium, magnesium, aluminium alloy or magnesium alloy; 1 then submit the plate to an oxidizing treatment, either chemically or electro-chemically, preferably to anodic oxidation, whereby the whole upper surface of the plate I including the faces of the indicia members 2 is provided with a coating 3 0f aluminium or magnesium oxide, as shown in Fig. 3. The next step is to polish or burnish the upper surface of the indicia members to remove the oxide coating therefrom while taking care not to deteriorate the oxide layer covering the remainder of the plate. The polished indicia members are thus made electro-conduotive whereas the remainder of the plate is kept insulated by the oxide coating. The dials are then subjected to electroplating in the usual conditions in order to cover only the prominent indicia members with the desired gal- Vanic coating 4 such as nickel, gold, silver or the like, whereas the background of the dial remains preserved by the insulating oxide layer 3. A dial is thus obtained which comprises a background of oxidized light metal with gilt, silvered or nickeleri prominent indicia members standing out in relief on this background.

As an optional modification, the light metal dial can be dyed during or after the anodic oxidation, in a single bath or in two successive baths. Optionally the background of oxidized light metal can be dyed after polishing and electroplating of the prominent indicia members. A dial is thus obtained which comprises nickeled, gilt or silvered indicia members standing out in relief on a coloured background.

What I claim is:

l. A process for manufacturing time-piece dials, comprising the steps of stamping indicia members in relief on a plate of light metal of the group consisting of aluminum and magnesium and alloys consisting predominantly of said metals, anodizing the plate to produce a nonconducting oxide coating thereon, abrading the upper surface of the prominent indicia members to remove the oxide coating therefrom and thereby make only the surface of said indicia members electro-conductive, and electro-plating said electro-conductive indicia members while the background of the plate is preserved by the oxide coating.

2. A process for manufacturing time-piece dials, comprising the steps of stamping indicia members in relief on a plate of light metal of the group consisting of aluminum and magnesium and alloys consisting predominantly of said metals, anodizing the plate to produce a nonconducting oxide coating thereon, abrading the upper surface of the prominent indicia members to remove the oxide coating therefrom and thereby make only the surface of said indicia members electro-conductive, electro-plating said electroconductive indicia members while the background of the plate is preserved by the oxide coating, and dyeing said dial subsequent to the formation of said oxide coating.

3. A process for manufacturing time-piece dials, comprising the steps of stamping indicia members in relief on a plate of light metal of the group consisting of aluminum and magnesium and alloys consisting predominantly of said metals, anodizing the plate to produce a nonconducting oxide coating thereon and simultaneously dyeing said dial, abrading the upper surface of the prominent indicia members to remove the oxide coating therefrom and thereby make only the surface of said indicia members electro-conductive, and electro-plating said electro-conductive indicia members while the background of the plate is preserved by the oxide coating.

CHARLES STERN.

(References on following. page) REFERENCES CITED Number The following references are of record in the 233331) file of this patent: 2,237,433 2,324,106 UNITED STATES PATENTS 5 2,430,468 Number Name Date 7 864,467 Ingraham" Aug. 27, 1907 1,373,430 Humphrey 5 192 Number ,7 ,778 Wheeler July 30, 1929: 5,167 2, 5,988 McNally ,,Ju1 .s, 1937 10;. 13, 96

Name Date Frasch Mar. 4, 1941 Graenacher et al. Apr. 8, 1941 Pettit July 13, 1943 Julich Nov. 11, 1947 FOREIGN PATENTS? Country Date Switzerland Mar. 4, 1913 Switzerland Feb. 16, 1926 

